1. Field of the Invention
The present invention relates to a liquid ejection head having good ejection characteristics and to a method of manufacturing such a liquid ejection head at low cost.
2. Description of the Related Art
It is known that one liquid ejection head can be constituted by aligning a plurality of head units, each formed with a plurality of nozzles (ejection ports), a plurality of pressure chambers connected respectively to the plurality of nozzles, and a plurality of actuators which eject liquid respectively from the plurality of nozzles by respectively changing the pressure inside the plurality of pressure chambers, together with a single common liquid chamber which supplies liquid to the plurality of pressure chambers.
Moreover, Japanese Patent Application Publication No. 2002-144576 discloses a liquid ejection head comprising an element substrate provided with a plurality of ejection ports and ejection energy generating elements, and a common liquid chamber.
Furthermore, Japanese Patent Application Publication No. 6-23988 discloses an apparatus comprising nozzles, pressure chambers which fill with ink, a pressurization device which applies pressure to the ink in the pressure chambers, and an ink storing unit which stores ink to be supplied to the pressure chambers, wherein the pressure chambers and the ink storing unit are mutually separated by means of a porous member.
There are demands for a full line type of liquid ejection head which achieves good ejection characteristics at low cost.
A full line type of liquid ejection head has a structure in which a plurality of nozzles are formed through a length corresponding to the full width of the ejection receiving region, and although such a head is capable of high-speed processing, it may involve possibilities such as high costs, ejection variations between the nozzles, and the like.
Furthermore, if it is sought to compose a long, bar-shaped liquid ejection head by means of a plurality of short head units, then there is also a possibility that the liquid in the common liquid chamber is liable to leak out between the head units.
In the head described in Japanese Patent Application Publication No. 2002-144576, a long bar-shaped liquid ejection head is composed by means of a plurality of short head units (element substrates), and therefore it is necessary to seal the gaps between the head units in such a manner that the liquid inside the common liquid chamber does not leak out from the gaps between the head units, but if it is sought to seal these gaps between the head units by means of a sealing material, then large areas where nozzles cannot be disposed are created in the gaps between the head units.
In the technology described in Japanese Patent Application Publication No. 6-23988, a porous member is provided between the ink accommodating unit and the pressure chambers, and therefore if it is sought to compose a long bar-shaped liquid ejection head by means of a plurality of short head units, the liquid passing through the porous member will leak out from the gaps between the head units.